Revert "Bump configurate to 4.1.2"

This reverts commit 8f45bbf872.

the "hack" we had to include both 3 and 4 in the runtime jar is not
working, and we can't exactly break this right now

gradle/libs.versions.toml

@@ -1,5 +1,5 @@
 [versions]
-configurate = "4.1.2"
+configurate = "3.7.3"
 flare = "2.0.1"
 log4j = "2.20.0"
 netty = "4.1.100.Final"